Opel Combo 1.7 TDi Review:

The Opel Combo 1.7 TDi had tickling surges when the accelerator was held still at around 2500 rpm when the vehicle was picking up. This was because the turbocharger was automatically spooled by the higher air flow in the exhaust, a result of the compressed air flow from the Surbo at that moment.

Another owner said that with Surbo, turbo lag was cut, and that the engine was less loud.